140 likes | 227 Vues
1.1 Populations and Ecosystems. Varinder Singh B. Learning Objectives. Understand the meanings of a few new, ecological terms. Understand the mechanics behind an ‘ecosystem’. Understand what a ‘niche’ is. Success Criteria. Relate the words to real-life ecosystems. Ecology – The Study Of.
E N D
1.1 Populations and Ecosystems Varinder Singh B.
Learning Objectives • Understand the meanings of a few new, ecological terms. • Understand the mechanics behind an ‘ecosystem’. • Understand what a ‘niche’ is.
Success Criteria • Relate the words to real-life ecosystems.
Ecology – The Study Of... • Ecology is about studying relationships between organisms and their environment. ENVIRONMENT The conditions surrounding an organism. The environment can be split into living and non-living components. Black Bear Catskill Mountains, NY
Environment • So, Environment = conditions surrounding an organism. • These conditions are either living or non-living. LIVING = BIOTIC NON-LIVING = ABIOTIC • Biotic factors can include things such as competition between individuals, predation and disease. • Abioticfactors can include things such as temperature, rainfall and natural disasters.
Biotic Factors Abiotic Factors Temperature Rainfall Light Natural Disasters Rivers • Competition • Predation • Disease • Availability of food
Ecosystem • An ecosystem is the largest level of organisation we study in ecology. • It’s an area in which organisms interact with both the environment and with each other. <- A Rainforest Ecosystem: The ecosystem is the entire area and what lives within it. The environment includes the conditions. Two Major Things About Ecosystems: There is an energy flow Recycling of elements
Energy Flow in an Ecosystem What is the ultimate source of energy for an ecosystem? Solar Energy The flow of energy in an ecosystem is as follows: Solar Energy Chemical Energy What kind of organisms are responsible for this flow? Plants (Photoautotrophs) Photosynthesis
Energy Flow in an Ecosystem The previous slide dealt with the overall flow of energy through an ecosystem, and how it originally enters it. However, there are other organisms involved as well as plants. Energy is transferred through trophic levels. Producer Primary Secondary Tertiary ConsumerConsumerConsumer All energy passing through the ecosystem is eventually returned to it as heat.
Populations • A population is a group of organisms of a SINGLE SPECIES, living in the same area, that breed together. Groby? • Boundaries of a population are hard to define. For humans it’s pretty easy, but for insects and migratory birds it can be difficult. log another log 1km
Community • A community is all of the populations in the ecosystem. • The populations in the community will be: • Living together • Interacting with each other • Killing and eating each other Remember: We’re not just talking about animals. Populations and communities include the plants too. Bats Anaconda Spiders Ants Birds Frogs Plants
Habitats • Within an ecosystem, there are many areas where organisms can live. These areas are called habitats. • The type of habitat depends on the species. • Mammalian habitats are different from amphibian or bird habitats. • Some habitats overlap. • Microhabitats are small pockets within an ‘ordinary’ habitat. • A python may live on a tree, but the cracks in the bark may be home to woodlice.
Niche • Think of every organism in an ecosystem as having a job there. • The environment dictates how the organism does it’s job. A NICHE refers to where an organism lives, and what role it plays within the environment. All of the biotic and abioticfactors of the environment influence the niche.
The ecological niche of an organism depends not only on where it lives but also on what it does. By analogy, it may be said that the habitat is the organism's "address", and the niche is its "profession", biologically speaking. Odum - Fundamentals of Ecology - W B Saunders 1959 Example: Oak trees live in oak woodlands. The oak woodland is the habitat. So if you were writing a letter to an oak tree, you would address the letter to: Sir Deciduous Oak Tree,The Oak Forest,England,U.K. What do oak trees do? If you can answer that question you know the oak trees "profession" or its ecological niche. Perhaps you think that oak trees just stand there looking pretty and not doing vey much, but think about it. Oak trees: • absorb sunlight by photosynthesis; • absorb water and mineral salts from the soil; • provide shelter for many animals and other plants; • act as a support for creeping plants; • serve as a source of food for animals; • cover the ground with their dead leaves in the autumn.